The present invention concerns a novel apparatus for weighing material being collected. Although the illustrative embodiment describes a system in which plasma that is separated from whole blood is being collected, it is to be understood that the apparatus and method of the present invention is applicable to weighing various materials being collected. Further, since weight is proportional to volume the apparatus and method of the present invention is applicable to determining the volume of material being collected. As used herein, the term "weight" should be considered as interchangeable with "volume".
Plasmapheresis involves the separation of plasma from whole blood, the collection of the plasma and the return of the red cells to the donor. It is desirable, if not essential, that the weight (i.e., volume) of the plasma being collected be monitored. In some cases, the plasma is collected in a disposable plastic container which may be hung from a suitable post or rack.
Monitoring the amount of plasma collected from a patient or donor is essential because the collection of too much plasma may be dangerous and it is desirable to effect a predetermined yield. Thus a doctor may weigh the patient or donor and determine from such weight how much plasma can safely be collected.
It is an object of the present invention to provide an apparatus and method for weighing material (such as plasma) being collected, with the provision of signaling or terminating the operation when a predetermined amount of the material has been collected.
Another object of the present invention is to provide an apparatus for weighing material being collected, which apparatus is relatively simple in construction and easy to manufacture.
A further object of the present invention is to provide apparatus for weighing material being collected, which apparatus is relatively accurate and employs digital circuitry.
Another object of the present invention is to provide apparatus for weighing material being collected, which apparatus is relatively insensitive to lead length and contact resistance.
A further object of the present invention is to provide apparatus for weighing material being collected, which apparatus operates automatically to compensate for the tare weight.
A still further object of the present invention is to provide an automatic system for weighing material being collected, which utilizes digital components and provides a result display.
Another object of the present invention is to provide apparatus and a method for weighing material being collected, which is simple to operate and is adaptable for measuring the weight or volume of plasma being collected during plasmapheresis.
Other objects and advantages of the invention will become apparent as the description proceeds.